stepper motor help??

[dynomyte]

Hello, I am trying to get more torque out of my stepper motor. I think that it isnt a problem with the controller. Is there a hardware way to get more torque?? any help would be greatly appreciated.

 

[Papabravo]

Do you need more holding torque, or do you need more torque at high speed?

For the first problem make sure there is sufficient current in your supply to allow the coils to draw their maximum current.

The second problem is more difficult to attack since the faster you go the less torque you get. This is typical of all motors. The other problem with steppers is resonance. If you try to run at a reonance point your torque will go to zero and stay there. You must run the motor either faster or slower.

 

[dynomyte]

I am working on a mixer of sorts, kinda like a blender, but using a stepper motor. The problem i am having is that if I use a viscous fluid then the motor will almost stop at any RPM value.

 

[Nigel Goodwin]

I am working on a mixer of sorts, kinda like a blender, but using a stepper motor. The problem i am having is that if I use a viscous fluid then the motor will almost stop at any RPM value.

So why are you using a stepper?, it seems a really poor choice for a mixer? - why would you want the ability to move a step at a time?.

 

[Papabravo]

Torque is proportional to current for any kind of motor. If you want more torque you need to move more current. If you want more torque at higher speeds then you need to ramp the velocity up and down to get smoothly through the resonance points.

To mix viscous liquids with a stepper you need a motor with 3-6 Amps per coil and a power supply of 12-25 Amps. Getting to reasonable RPM as Nigel points out is difficult with a stepper.